Every game platform has its flagship. For Nintendo, it’s anything Mario. For the Xbox, it’s all things “Halo.” Can “LittleBigPlanet” be that game to the third-place PlayStation 3 platform? Sony hopes so. And actually, so do I.

“LittleBigPlanet" is a new platformer game for the PlayStation 3. In it, you’ll journey around a planet — a little big planet — that looks an awful lot like ours, but in some surreal parallel universe where cars are made of cardboard and meerkats can be used as trampolines. In it, you’ll run, jump and collect goodies in levels that are easily identifiable as a real-life place, but in a Salvador-Dali-meets-Tim-Burton way. Somehow, it works.

Beyond the stellar art direction, “LittleBigPlanet,” which hits shelves Oct. 21, is unique and utterly charming. There’s a great co-op mode, so casual players can play alongside those for whom the PlayStation controller fits like a comfy old shoe. And hardcore gamers needn’t be put off by the “cute factor” of “LittleBigPlanet.” The game serves up some seriously challenging gameplay and offers almost endless replayability — particularly when you factor in user-created levels.

Did I mention that it’s gorgeous, too?

Oh my, it’s a sight to behold. British developer Media Molecule has created dazzling visuals that are richly detailed and so realistic that they seem like they’re going to jump off the screen. The levels are stunning and the objects look as though they’ve been handcrafted by a master toymaker. And the controls are simple: run left to right, jump, grab, try not to impale yourself on a spike.

In the game, you play Sackboy (or Sackgirl, if that’s your bag). You start out by customizing your Sack — new mouth, new eyes, a lovely frock or two. You get more options the more you progress in the game. At the moment, my Sackgirl is sporting a wedding dress, a Roman helmet and a zebra tail.

Sounds zany? You’re darn tootin’. This game is off-the-wall wacky, but in a British way, not a Japanese-game-show way. Your missions include training to be a ninja with Grandmaster Sensei and dragging a meerkat from a meerkat “gentleman’s club.” (It all makes sense eventually.)

“LittleBigPlanet” is simple enough for anyone to grasp, but it’s hardly easy. Some levels are tough to the point of controller-flinging. But each level has multiple checkpoints, and you get several tries for each checkpoint. If you get too frustrated, “LittleBigPlanet” has quick little mini levels that let you race the clock to accomplish some specific goal. All of these wins add up, boosting your level scores and giving you new goodies to play with.

The game relies heavily on physics, which means things behave the way you’d expect them to. Fire logs roll realistically down hills, the rope swing you use to transport you over a pit of toxic soup swings and sways with momentum you create. And things feel like they have weight, as if you could reach out and touch them.

But as great as the game is, the user-generated levels distinguish “LittleBigPlanet” from anything else out there. After you’ve completed the third level in the game, you gain the ability to make your own levels. You’ll start off with a pretty limited set of tools, but each tutorial you do explains the tools and unlocks new ones. Within an hour, it’s possible to have a simple level — with pits of fire, spikes and checkpoints — up and running.

If you want something more involved, though, that will take work: planning, trial and error and play-testing to see if your level actually works. Doing this with a PlayStation 3 controller instead of a mouse and keyboard can be a test in patience. But this game really walks the talk, taking creativity and user-generated content to a level not yet seen in games.

The tag line for “LittleBigPlanet” is “Play. Create. Share,” and many players have already shared their creations — over 3,000 levels in the first 24 hours of the beta — with the wider community. The “cool levels” portion of the game is like YouTube: Players upload their work, other players play them and then rate them, assigning them adjectives such as “brilliant,” “easy” or “artistic,” among others.

My husband, who makes video games for a living, got lost in this portion of “LittleBigPlanet” and hasn’t been seen much since. On a sunny Sunday, he sat in our basement, honing and polishing his level while our pets snoozed around him. When asked by a reporter if he planned to post the bloody thing, he said, “It’s not ready yet.”

It’s also possible to lose hours playing through the user-created levels. Players have already made some really amazing stuff, including a “Grand Theft Auto”-themed level, a “PS3 or Xbox 360” level and one that’s an homage to “Shadow of the Colossus.” My personal favorite, though, is the level where you ride in a vehicle, and each block you pass plays a note to the song “Sweet Child O’ Mine” by Guns N’ Roses.

These user-created levels add tons of gameplay to this already feature-rich game, which makes “LittleBigPlanet” a fantastic bargain for the $60 price. And that will undoubtedly be a factor for many people in the months to come.

That brings up the one bummer about “LittleBigPlanet:” It’s only available on the PlayStation 3 platform. In fact, Sony is banking on this game to move consoles this holiday season. Any other year, this would be a slam dunk — “LittleBigPlanet” is the kind of game that people buy consoles for. But in late 2008, folks who just six months ago would have plunked down $400 for a new PS3 are feeling understandably frightened about their financial futures.

“LittleBigPlanet” isn’t the only pro in the PS3 column. Sony is launching the long-delayed online community it’s calling "Home" later this year. The PlayStation 3 also includes a built-in Blu-ray player. And after a slow start, more games are coming to the system, including the next installments to fan favorites “Final Fantasy” and "Gran Turismo."

Whether or not Sony can sell consoles this Christmas depends a lot on forces beyond the company’s control. And that’s too bad. This game likely will be an instant classic, one that deserves a place on any gamer’s shelf — not just those who happen to own a PS3. If you don’t have a PS3, make good friends with someone who does. “LittleBigPlanet” will keep you occupied and entertained for hours, through the long, cold winter and beyond.